Digital printing involves technologies in which a printed image is created directly from digital data, for example using electronic layout and/or desktop publishing programs. Methods of digital printing include full-color ink-jet printing, electrophotographic printing, laser photo printing, and thermal transfer printing methods.
Electrophotographic printing techniques involve the formation of a latent image on a photoconductor surface mounted on an imaging plate or other surface. In one instance, the photoconductor is first sensitized, usually by charging, and then exposed to light projected through a positive film of the document to be reproduced, resulting in dissipation of the charge in the areas exposed to light. The latent image is subsequently developed into a full image by the attraction of oppositely charged toner particles to the charge remaining on the unexposed areas. The developed image is transferred from the photoconductor to a hot elastomeric blanket, from which it is transferred to a substrate, such as paper, plastic or other suitable material, by heat or pressure or a combination of both to produce the printed final image.
The latent image is developed using, either a dry toner (a colorant mixed with a powder carrier) or a liquid ink (a suspension of a pigmented resin in a liquid carrier). The toner or ink generally adheres to the substrate surface with little penetration into the substrate. The quality of the final image is largely related to the size of the particles, with higher resolution provided by smaller particles. Further, it can sometimes be desirable to have toner concentrations with relatively high solids content, however the manufacture liquid toner compositions with high solids content toners is challenging.